Fluid coupling and clutch



March 6, 1951 J. B. BLACK FLUID COUPLING AND CLUTCH 3 Sheets-Sheet 1 Filed July 9, 1947 March 6, 1951 J. B. BLACK FLUID COUPLING AND CLUTCH 3 Sheets-Sheet 2 Filed July 9, 1947 March 6, 1951 J. B. BLACK FLUID COUPLING AND CLUTCH 3 Sheets-Sheet 3 Filed July 9, 1947 firms 6 51444.

13- d e az- Patented Mar. 6, 1951 UNITED STATES PATENT I OFFICE rwm coornmc arm cnn'rcn James B. Black, Rockford, 111., assignor to Twin Disc Clutch Company, Racine, Wis, a corporation of Wisconsin Application July 9, 1947, Serial No. 759,829

1 My invention relates to power transmissions and more particularly to an arrangement incorporating provision for hydraulically transmitting power to the load during the starting and accelerating period and for direct transmission when the load reaches a desired speed in conjunction with the ability to effect a full power shift from one drive to the other in either direction.

hydraulic to direct drive, or vice versa, when the engine is not connected to the load and hence will accelerate rapidly which is objectionable. For example, in a typical unit wherein a hydraulic torque converter provides the hydraulic drive, the power source is selectively connected to the converter or directly to the driven shaft through friction clutches and in shifting from one drive to another, the unavoidable time required to disengage one clutch and engage the other leaves an interval when the power source is unconnected to the load.

Even in the so-called Hydramatic transmission for motor vehicles which is sometimes referred to as a power shift unit, the shifting from one speed to the next requires the simultaneous release of one friction band and the engagement of another. This operation requires careful timing and close adjustment since if one gear engages slightly before the preceding gear is released, the transmission is for the time being in two gears simultaneously which imposes considerable strain on the parts and causes the vehicle to slow down' rapidly, while if the timing is slow, the engine is temporarily disconnected from the drive shaft and accelerates rapidly during this period.

It is therefore one object of my invention to devise a power transmission arranged for selective hydraulic or direct drive in which provision is made for shifting from one drive to the other in either direction without at any instant interrupting full power flow through 'the unit so that the engine or other power source is at all times coupled to the load.

A further object is to provide a transmission of 3 Claims. (Cl. 192- 33) 2 the character indicated in which the hydraulic drive function is performed by a hydraulic torque converter which during the period of hydraulic drive always operates as a converter and hence may be designed for maximum efliciency for this purpose.

A further object is to provide a transmission as above stated which is equipped with hydraulically actuated clutches whose selective or combined operation determines the conditioning of the unit for hydraulic or direct drive.

These and further objects of the'invention will be set forth in the following specification, reference being had to the accompanying drawings, and the novel means by which said objects are eifectuated will'be pointed out definitely in the claims.

In the drawings:

Fig. 1 is a sectional elevation of the upper half of the transmission. the clutches being shown in disengaged position.

Fig. 2 is a fragmentary, sectional elevation of the unit as it appears in Fig. l, the section through the dump valves for the clutches and the passages leading thereto being taken along the line 2-2 in Fig. 3.

Fig. 3 is a section of the dump valves and passages taken along'the line 3-4 in Fig. 2.

Fig. 4 is a fragmentary section showing the shifted position of the dump valve when pressure is applied to the hydraulic drive clutch.

Fig. 5 is a schematic layout of the pressure system leading to the clutches and the pump and control valve therefor, the clutches being disengaged.

Fig. 6 is an enlarged section of the control valve, the rotor being positioned to admit actuating oil to the hydraulic drive clutch.

Referring to Figs. 1 and 2, the numeral l0 designates a flywheel driven by an engine (not shown) and having bolted thereto a ring II which is internally splined for driving engagementwith an externally splined sleeve I2 that is coaxial with the flywheel. This method of driving the sleeve I2 is by way of example only since other power sources may be employed, including non-prime movers. The left end of the sleeve i2 is piloted in the flywheel In while the right end is journaled on a driven shaft presently described by means of a roller bearing H. A carrier ring I5 is interposed between the sleeve l2 and a flanged portion 10 of the transmission housing, the ring being provided with piston rings It for sealing contact with the flange. The right end of the sleeve l2 carries a transversely related disk ll whose right face, or the face away from the flywheel, is recessed to provide concentric, annular cylinders l8 and I8. the iormer being disposed radially outward of the latter. The disk I! forms the closed ends of the cylinders and extending from the disk beyond the open ends of and between the cylinders is an externally and internally splined or toothed annulus "having outer and inner shoulders 2| and 22, respectively, located at the exposed extremity thereof.

An annular piston 23 is slidably mounted in the cylinder l8 in actuating relation to a plurality of clutch plates 24, alternate plates'having driving and sliding engagement with the outer splined surface of the annulus 26 while the remaining plates are similarly engaged with one end of a driving ring 25 whose opposite end is bolted to the bladed pump 26 of a hydraulic torque converter 21. The plates 24 are engaged by the piston 23 against an abutment ring 28 slidable on and having splined engagement with the outer surface of the annulus 2|] and whose movement during engagement of the plates is limited by the shoulder 2|. The piston 23, plates 24 and ring 28 constitute the hydraulic drive clutch 66 of the transmission (see Fig. 5).

An annular piston 29 is slidable in the cylinder 7 l8 and is operably related to a plurality of clutch plates 30, alternate plates being drivably and slidably engaged with the inner surface of the annulus 20 and an externally splined hub 3| respectively, the hub being keyed to a driven shaft 32 coaxial with the flywheel i0 and the clutch plates 24 and 30. The plates 30 are engaged by the piston 29 against an abutment ring 33 slidable on and having splined engagement with the inner surface of the annulus 20 and whose movement during engagement is limited by the shoulder 22. The piston 28, plates 30 and ring 33 form the direct drive clutch 63 of the transmission (see Fig. 5).

The converter pump 26 is journaled on the shaft 32 by a ball bearing 34 and its outlet and inlet ends are respectively operably related to connected, bladed turbines 35 and 36 constituting first and second stages of the converter and which are keyed to the shaft 32. The bladed, reaction member 31 is located between the turbines 36 and 36 and functions in the characteristic manner with respect thereto when power is transmitted through the converter. A sleeve 38 is secured at one end to the member 31 and is journaled on and in spaced, concentric relation to the shaft 32 by a ball bearing 39. Interposed between the opposite end of the sleeve 38 and a hub 48 forming part of the housing I3 is a freewheel or overrunning clutch 4| of characteristic construction which is arranged to hold the reaction member 31 stationary during power transmission throughthe converter and to permit it to rotate with the pump 26 and turbines 35 and 36 during direct drive. One end of the shaft 32 is jour- Selective hydraulic actuation of the hydraulic and direct drive clutches is accomplished by the following instrumentalities (see Figs. 1, 2 and 6). A sprocket 44 is secured to the sleeve I2, thus being directly driven by the power source, and is drivably connected to a sprocket 46 keyed to the driving shaft 46 of an oil pump 41 mounted interiorly of the housing I3. The pump inlet connects by a pipe 48 (see Figs. 1 and 5) with a sump 48 formed in the bottom of the housing l3 and a discharge pipe 66 leads from the pump to a port 6| provided in the casing of a control valve 62 mounted exteriorly of the housing l3 for convenient access by the operator. A pressure relief valve 63 of typical construction is bridged around the pump in communication with the pipes 48 and 66 to relieve the pipe 68 when the pressure therein exceeds a predetermined value.

The casing of the control valve 62 includes a port 64 communicating with a pipe 56 for supplying actuating oil in the manner presently described to the hydraulic drive clutch 66, a port 61 communicating with a pipe 68 for supplying actuating oil to the direct drive clutch 68, and a. port 60 communicating by way of a pipe 6| with the sump 49. A rotor 62 is rockable in the valve casing and may be externally actuated by a control handle (not shown). Arcuate channels 63 and 64 are recessed in the periphery of the rotor 62 and when the latter is in the position shown in Fig. 5, the channel 64 connects the ports 54 and 61 with the port 60 and hence with the sump 49, while the channel 63 communicates only with the port 5|, the pump 41 bypassing the oil through the relief valve 53. This position of the valve corresponds to disengaged positions of the clutches 66 and 69 with the power source idling.

The details of the hydraulic circuits between the control valve 62 and the clutches 66 and 68, shown diagrammatically in Fig. 5, are illustrated in detail in Figs. 2 and 3 to which reference will now be made. The pipes 66 and 58 extend through the housing l3 and their delivery ends communicate, respectively, with the outer ends of passages '68 and 69 provided in the flanged portion 10 of the housing l3 in which fits the carrier ring l6. The inner ends of the passages 68 and 68 communicate, respectively, with annular channels II and 12 in the outer periphery of the ring l6 and the latter are in constant communication through radial passages 14 and 16 with naled in the hub 40 by a ball bearing 42 and extends beyond the hub'for coupling to a load while the opposite end is piloted in the flywheel and specifically in the piloted end of the sleeve l2 by a bearing 43. The working liquid in the converter 21 is sealed by piston ring sealing members I09 and H8 interposed, respectively, between the shaft 32 and the pump 26 and hub 46, and

a similar sealing member I H is positioned between a suitably shaped portion of the housing I 3 and an annular shell H2 bolted to the pump 26 in enclosing relation to the turbines 36 and 36.

annular channels 16 and '11, all respectively, provided in the inner periphery of the ring ii.

The channel I! constantly communicates through radial passage 18 and longitudinal passage 18 in the sleeve l2 with the inner end of a radial passage in the disk H. The outer end of the passage 80 (see Fig. 3) connects by a transversely related passage 8| 'with an elongated, radial pocket 82 extending inwardly from the periphery of the disk I I, the outer end of the pocket being closed by a plug 83. Slidable in the pocket 82 is a piston dump valve 84 which, in the position of parts shown in Fig. 2, is maintained in an outer position by a spring 86 interposed between the end of the pocket and the head of the valve which is inwardly disposed.

The valve 84 includes an internal bore 86 whose inner end is closed by the valve head and the lateral surface of the valve skirt is Messed to provide spaced, annular grooves 81 and 86, the former being positioned radially outward of the latter which possesses the greater height for a purpose presently explained. The bore 86 and the channel 88 areat all times connected by ports 89in the skirt of the valve 88. when the valve 88' is in the position shown in Fig. 2, the V roove 81 communicates through outlet and discharge ports 98 and 9|, respectively, in the disk II with the cylinder I8 and the interior of the housing I3 and therefore the sump 89, while the groove 88 registers with the discharge end of the passage 8| and ,a land 84" provided onthe valve 84 masks an inlet port 82 which communiel tes with the cylinder I8. It will be noted that the height of the groove 88 is sufiicient to provide a radially outward overlapof the discharge end of the passage 8| in the position shown so that it is possible for the valve 88 to move inward for some distance without masking. this discharge end. A port 92! provides communication between that part of the pocket 82 which is occuplied by p the spring 8.5 to preventoil lockingin this portion of the pocket which might otherwiseinter- {era with inward movement of the dump valve 88.

For. the purpose of actuating the direct drive clutch 59, oil delivered to the channel 16 (see Fig. 2) flows-through a'radlal passage 93 anda longitudinal passage 94 in the sleeve I 2 tothe inner end. of a radial passage 95 in the disk-I1. The passage 95 connects by a transversely related passage 98 with a radialpocketil'l extending inwardly from the peripheryof the disk IT and which-is similar to the pocket 82. Blend 9'! may bediametrally related and since the latter is intended gtbservice' the direct-drive clutch, its length is greater than the pocket 82.

Slidablein the pocket 91 isa piston dump valve as which is similar to the valve an and is biased in: the outer position shown in Fig; 3, corresponding to a disengagement of the direct drive clutch 59 by a spring 99'Which' seats 'on the inner end-f the pocket and-abuts the valve against an elongated plug 188 which closes the outer end' transmission housing I3 and therefore the sump.

The grooves IN and I85are related to the ports I88, I88 and I8| in the same manner and for the samepurpose as the grooves in the dump valve 88 are related to the parts associated therewith. A

port I88 also communicates the spring end of the pocket 91' with the interior of the'housing I3 to prevent'oil locking f x V Considering the operation of the transmission with the control valve rotor 82 inthe position shown in Fig. 5 and the engineidling, oil iscirculated' by the pump 41 through the relief valve 53,

, the ports Hand 51 connect by way of the channel 88 and pipe 8lwith thesump 49 so that actuating pressure is not present in the pipes 55 and 58, and the. dump valves 84 and 98, occupy the positions shown-in Figs. 2 and 3. Under these conditions, the clutches 58 and 59 are disengaged and the engine is disconnected from the shaft 32.

' in connecting the engine to the load, advantage is taken of the high starting torque and capacity for rapid, smooth acceleration afforded by the converter and to drive through this unit, the valve The pockets" rotor 82 is rocked clockwise to the position-shown in Fig. 6 in which the channel 88 connects the ports 8| and 88 whereupon the pressure'of the pump 81 becomes effective in the pipe 88 and thence through connecting passages 18, I9, 88 and 8| in the sleeve I2 and disk II to that portion of the pocket 82 included in the groove. The oil then flows through port 89to the interior of the dump valve 84, thus forcing this valve radially inward against the spring 85 to the position shown in Fig. 4; In this position, the valve skirt outwardly of the groove 81 masks the outlet port 98 and the discharge port 9 I, while the inlet port 92 is unmasked so that pressure builds up in the cylinder I8 to thereby shift the piston 23 to engage the clutch 88. In the position of the valve rotor 82 shown in Fig. 6, the channel'83 is displaced from the port 51 and hence pressure is not effective in the cylinder I9 and the direct drive clutch 89 remains disconnected.

With the clutch 58 engaged, the engine is con- =nected to the shaft 32 through the torque converter 21 with the reaction member 31 held from rotating in reverse direction by the overrunning clutch 8 I. When the load is accelerated to the desired speed, the control valve rotor 82 is further rotatedin aclockwise direction to additionally register the channel 83 with the port 51,, pressure being maintained through'the' port 58 and hence engaging pressure is maintainedon the hydraulic drive clutch 58. f V I The pressure established in the pipe 58 thereupon becomes efiective through the passages. 99, 98, 95 and 98 in the sleeve. I2 and disk Ilt'o that portion of the pocket 9]! included in the groove I8I. The oil then flows through port I82 to the interior of-i the dump valve 98, thus forcing this valve radially inward against the spring 99 to a position in which the outer skirt portion offthe valve masks the outlet port I88 and discharge port I81 while the inlet portiIM is unmasked and register with the groove I8 I, the conditions being similar to those discussedin connection with the dump valve88.

, Pressure. is accordingly'built up in the cylinder I9 to thereby engage theclutch 59 and establish direct drive between the power source and the shaft 32. Prior to this direct drive connection,

thespeed of the shaft 32 is less than the engine speed due to the usual loss through the converter, but when the clutch 59 is engaged, the shaft speed .is equalized with that of the engine.

Under these conditions and since thehydraulic 'drive clutch 58 remains engaged, theconverter pump 28 and turbines 35 and 36 rotateat the same or engine speed. Hence, there will not be any reaction against the blades of the reaction I member 31 and the latter, as it is released by the overrunning clutch II, will begin to rotate with the pump and turbines. Since power is not then being transmitted through the converter and all parts thereof'arerotating at substantially the same speed, the power lossesin the converter circuit are negligible. Actually, the reaction member 31 rotates at a slightly slower speed than the pump and turbines due to the drag of the bearings and the overrunning clutch-but the diner- "ence is smalL- d If the load becomes tooheavy to be carried in direct drive, the control valve rotor 82 is rocked counterclockwise to the position shown in Fig. 6, thereby interrupting the oil pressure to the pipe 88 and hence to the direct drive clutch 89. Since theoil pressure is not effective within the dump valve 08, the spring on returns the valve from its then inward shifted position to that shown in Fig. 2 to unmask the ports I08 and it! and permit discharge of the oil in the cylinder It to the sump. Therefore, the direct drive clutch t! is disengaged and power drive is then through the converter 21.

The outstanding advantage of the above construction is that the transmission is characterized by a full power shift, the engine at no time being completely disconnected from the load. As load conditions vary, the drive through the transmission may be shifted at will from hydraulic to direct drive and vice versa with the hydraulic drive clutch it being always engaged.

Power flow through the transmission may be interrupted by turning the valve rotor 82 to the position shown in Fig. 5. If the position of the rotor prior to turning is that corresponding to direct drive, then the Fig. position cuts oil oil pressure to both clutches and the dump valves 84 and it are returned to the positions shown in Fig. 2 to discharge oil from the clutch cylinders it and it, respectively. but if the transmission is in hydraulic drive, then moving the rotor 82 to the Fig. 5 position only denies pressure to the clutch it since the clutch 50 is already disengaged and the dump valve it alone is moved to the discharging position shown in Fig. 2 by the spring Ii.

The special design of the dump valves It and it provides assurance that the associated clutch cylinders will be rapidly and completely emptied. Without such valves. the centrifugal pressure head developed in the oil by the rotating disk il would be sumcient to keep the clutches engaged and if the only discharge route for the oil was through the supply passages, quick disengagement of the respective clutches would be impossible. The dump valves solve this problem since they are located immediately adjacent the associated clutch cylinders. Centrifugal force and the bias provided by the spring 85 tend to keep the valve 84 in the discharging position shown in Fig. 2 and when oilpressure is admitted to the pipe 55 leading to the clutch 58, the valve is moved inwardly to the position shown in Fig. 4

against the spring 85 and centrifugal force acting on the valve. The weight of the valve is such that when oil pressure to the clutch 56 is out oh, the centrifugal force effective on the valve equals the centrifugal pressure head developed in the oil so that the spring 85 returns the valve to the discharge position. The dump valve 98 operates in like manner.

I claim:

1. In a power transmission, the combination of a driven shaft, hydraulic power circuit means connected to the shaft, first hydraulically actuated clutch means for connecting the circuit means to a power source, second hydraulically actuated clutch means shiftable between positions providing and interrupting a direct drive between the source and shaft while the first clutch means is engaged, and a hydraulic pressure system including both clutch means and a control valve, the valve being operable to determine the actuation of both clutch means.

2. In a power transmission, the combination of a driven shaft, a hydraulic torque converter including a pump member, a turbine member and a reaction member, the turbine member being keyed to the shaft and an overrunning clutch being interposed between the reaction member and a fixed part of the transmission, first hydraulical- 10 3. In a power transmission, the combination of a driven shaft, a hydraulic torque converter including a pump member, a turbine member and a reaction member, the turbine member being keyed to the shaft and an overrunning clutch being interposed between the reaction member and a fixed part of the transmission, a member arranged for connection to a power source, outer and inner, concentric and hydraulically actuated, friction clutches carried by the member, friction parts of each clutch being drivably connected to the member, other friction parts of the outer clutch being drivably connected to the pump member and other friction parts of the inner clutch being drivably connected to the shaft, and a hydraulic as pressure system including both clutches and a control valve, the valve being operable to determine the actuation of the outer clutch and selectively the engagement and disengagement of the inner clutch while the outer clutch is engaged.

3o 4. In a power transmission, the combination of a driven shaft, hydraulic power circuit means connected to the shaft, a member arranged for connection to a power source, outer and inner, concentric and hydraulically actuated friction clutches carried by the member, friction parts of each clutch being drivably connected to the member, other friction parts of the outer clutch being drivably connected to the circuit means and other friction parts of the inner clutch being drivably connected to the shaft, and a hydraulic pressure system including both clutches and a control valve, the valve being operable to determine the actuation of the outer clutch and selectively the engagement and disengagement of the inner clutch while the outer clutch is engaged.

5. In a power transmission, the combine. .on of a driven shaft, hydraulic power circuit mean connected to the shaft, a disk arranged for connection to a power source and recessed in one face to provide concentric, annular cylinders, a piston slidable in each cylinder, outer and inner, friction clutches carried by the disk and engageable by the respective pistons, friction parts of each clutch being drivably connected to the disk.

other friction parts of the outer clutch being drivably connected to the circuit means and other friction parts of the inner clutch being drivably connected to the shaft, and a hydraulic pressure system including a control valve, both cylinders each of which is provided with an inlet port and an outlet port providing communication between the associated cylinder and an adjacent pocket in the disk, each pocket including a discharge port communicating with the transmission sump, and a piston dump valve slidable in each pocket and biased to a position in which the outlet and discharge ports for the associated cylinder are placed in communication, the control valve being operable to admit the system liquid to the interior of the outer cylinder dump valve to shift the latter to a position masking the outlet port and admitting system liquid to the outer cylinder to engage the outer clutch and selectively operable to admit or deny system is engaged.

6. In a power transmission, the combination of a driven shaft, hydraulic power circuit means connected to the shaft, first hydraulically actuated clutch means for connecting the circuit means to a power source, second hydraulically actuated clutch means shiftable between positions providing and interrupting a direct drive between the source and shaft while the first clutch means is engaged, and a hydraulic pressure system including both clutch means and a control means, the control means being operable to determine the actuation of both clutch means.

7. In a power transmission, the combination of a driven shaft, a hydraulic torque converter including a pump member, a turbine member and a reaction member, "the turbine member being keyed to the shaft and an overrunning clutch being interposed between the reaction member and a fixed part of the transmission. a

member arranged for connection to a power source, outer and inner, concentric and hydraulically actuated, friction clutches carried by the member, friction parts of each clutch being drivably connected to the member, other friction parts of one clutch being drivably connected to the pump member and other friction parts of the other clutch being drivably connected to the shaft, and a hydraulic pressure system including both clutches and a control means, the control means being operable to determine the actuation of the pump connected clutch and se- 10 lectively the engagement and disengagement of the shaft connected clutch while the pump connected clutch is engaged.

8. In a power transmission, the combination of a driven shaft, hydraulic power circuit means connected to the shaft, a member arranged for connection to a power source, outer and inner, concentric and hydraulically actuated friction clutches carried by the member, friction parts of each clutch being drivably connected to the member, other friction parts of one clutch being drivably connected to the circuit means and other friction parts of the other clutch being drivably connected to the shaft, and a hydraulic pressure system including both clutches and a.

control means, the control means being operable to determine the actuation of the circuit means connected clutch and selectively the engagement and disengagement of the shaft connected clutch while the circuit means clutch is engaged.

JAMES B. BLACK.

REFERENCES CITED The following references are of record in the file of this patent:

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